Sealing Grommet And Method Of Filling

ABSTRACT

The grommet used for sealing the charging opening in a pressurized dispensing container is designed so that it can be held in a venting state prior to the charging of the propellant chamber. The design involves an annular ridge above the neck of the grommet and an annular groove above the annular ridge. In that fashion, the grommet can be held loosely on the opening in the base of the container. Flats or cutaways on the crown and groove assure passageway between the propellant chamber and the outside so that air can be taken in and expelled from the propellant chamber during the product loading stages.

BACKGROUND

The sealing grommet of this invention is an improvement to the sealing grommet design shown in Applicant's U.S. Pat. No. 6,729,362 issued on May 4, 2004 and entitled: Sealing Grommet. The contents of this '362 patent are incorporated herein by reference.

This sealing grommet is adapted to seal the base of a pressurized dispensing container and thus seal the propellant chamber.

The Sealing Grommet described in the '362 patent permits mounting the sealing grommet in a sealed state before the propellant chamber is charged with propellant. By stretching the neck of that grommet with the use of a pin, openings in the base of the grommet are placed in communication with the propellant chamber of the dispensing container. When the propellant chamber is fully pressurized, the stretch pin is removed and the grommet snaps back to its sealed state. This keeps the propellant chamber sealed under pressure so that pressure is deliverable to dispense product through the valve at the top of the container.

During loading of product into the container it is often necessary that the propellant chamber be able to vent air prior to it being pressurized and sealed by the grommet.

It enables faster and more economic filling to have the sealing grommet mounted in the opening at the base of the container during the whole process of product fill so that the grommet does not have to be placed at the base opening after the product filling stage and before the pressurization stage.

Accordingly, it is a purpose of this invention to provide a sealing grommet design for the opening in the base of a pressurized dispensing container in which the grommet will permit venting during the product filling stage and will be immediately accessible to seal the base of the container after the propellant chamber is charged with propellant.

It is a related purpose of this invention to provide the above purpose with a grommet that will be held in the opening at the base of the container without falling out during the product loading steps.

BRIEF DESCRIPTION

The grommet of this invention seals the small charging opening in the base of the pressurized dispensing container in a fashion described in the '362 patent.

However, in the design of this invention, an annular groove is created in the crown of the grommet above the neck. The groove is spaced from the neck by an annular ridge. The grommet is held in the container base opening before product is loaded into the container. The crown above the grove catches the edge of the container base opening. In this fashion, the grommet is held at the container base opening before the grommet is placed in its sealed state. During this holding stage, product is filled into the product chamber in a fashion that requires venting of the propellant chamber through the container base opening.

Cutaway flats in the annular crown and groove create a passageway between the propellant chamber within the container and the outside during this holding stage. Thus during the product loading stage, when air has to be vented in and out of the propellant chamber, such air can pass through the passageway created by the flats.

After the product has been properly loaded into the product chamber, it is time to charge the compressed air into the propellant chamber. To do so, the grommet is pushed further into the container so that the neck of the grommet engages the edge of the container base opening, thus providing a seal. The propellant is then injected by stretching the neck of the grommet to expose holes through the base of the grommet to the propellant chamber so that pressurized gas propellant can be injected. This propellant injection procedure is described in greater detail in the '362 patent.

DESCRIPTION OF THE FIGURES

FIG. 1 is an illustration of the prior art from the '362 patent showing the grommet in the state where pressurized gas is injected through the openings 24.

FIG. 2 is an elevation view of the grommet of this invention in its venting state position, where the grommet 30 is held in a non sealing state by the opening 18 of the base 20 of the container.

FIG. 3 is a cross-sectional view along the plane 3-3 of FIG. 2, illustrating the flats 36 of the grommet.

FIG. 4 is an elevation view of a portion of the FIG. 2 view with arrows showing the path of air into the propellant chamber of the container.

FIG. 5 is a longitudinal sectional view in the sealing state of the embodiment disclosed herein

FIG. 6 is a longitudinal sectional view through two of the flats 36.

FIG. 7 is a longitudinal sectional view similar to that of FIG. 6 except that it is taken along a plane which does not intersect any portion of the flats 36.

FIGS. 8-11 illustrate how the grommet of this invention is deployed during the loading of product into the product chamber prior to pressurizing the propellant chamber.

More specifically, FIG. 8 shows the stage where product has just been placed into the container.

FIG. 9 shows the stage where slight pressure is applied to push the product down around the piston so as to minimize air space under the product. At this stage, some venting of air out of the container is required as air is pushed around the piston and out the base of the container. At this stage the grommet 30 is in its venting state as shown in FIGS. 2 and 4.

FIG. 10 shows the stage where the product is pushed up to fill the upper portion of the container. This stage requires the venting of air into the propellant chamber of the container.

FIG. 11 shows the stage where the pressurized propellant has been inserted into the propellant chamber to provide the pressure necessary to dispense product when the product valve 50 is open. This stage requires that the grommet 30 be in its sealed state shown in FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The Figures relate to a single embodiment except that FIG. 1 illustrates the prior art on which this invention is an improvement. FIG. 1 is taken from FIG. 9 of the '362 patent.

As shown in FIG. 1, the prior art sealing grommet 10 has a crown 12, a base 14 and a neck 16 connecting the crown 12 to the base 14. The grommet 10 is shown seated in the opening 18 in the base 19 of the container. A pin 26 is used to push the crown 12 up and stretch the neck 16 so that the openings 24 in the grommet will be stretched to the point where there is communication between the inside of the container and the outside. This permits charging a propellant into the pressurized chamber of the dispensing container with which this grommet is used. After the propellant chamber has been charged with pressurized fluid, the pin 26 is removed and the neck 16 retracts to provide a sealing relationship between the grommet 30 and the opening 18 of the container base 20.

During the loading of product into the pressurized container, there is a procedure which is described in greater detail in connection with FIG. 8 through 11 in which it is important to vent air into and out of the pressurized chamber before the chamber is pressurized. It is further important that the grommet 30 be held by the container opening 18 during the product loading stages. This importance arises out of two related reasons.

First, it is important that the grommet be available to be forced into its sealing state as soon as the charging of propellant into the pressurized chamber is completed.

Second, it is convenient to have the grommet in place during the filling and pressurizing stages as this saves steps in assembly.

The grommet 30 that is an embodiment of this invention, has the crown 12, stretchable neck 16 and base 14 similar to the prior art grommet 10. However, the grommet 30 disclosed herein also has an annular ridge 32 above the neck 16 and an annular groove 34 above the ridge 32. Both the ridge 32 and groove 34 are below the crown 12. The diameter of the crown 12 is greater than the diameter of the container charging opening 18 so that the grommet 30 will be held at the opening 18 and will not fall out during the product filling steps.

During the product loading stages, prior to the charging of propellant into the pressurized chamber, the grommet 30 is loosely held in the opening 18 of the container base 20. A set of four flats 36 are cut across the surface of the crown 12 and groove 34. Thus, in the FIG. 2 venting state, there is ready communication between the interior of the container which is above the flats 36 and the outside. This communication can be better visualized in FIG. 4. The communication occurs through a passageway defined by the edge of the container opening 18 and the flat surfaces 36 of the grommet 30.

FIG. 4 shows the path of air from the outside into the chamber that is to be pressurized during the product loading stages which require venting. This venting can go either direction as required by the stages illustrated in FIGS. 9 and 10.

After product has been loaded and the pressurized chamber is fully charged, the base 14 of the grommet is forced upward to immediately switch the grommet from the venting state as shown in FIG. 4 to the sealing state as shown in FIG. 5.

The flats 36 are the most convenient way to provide the venting openings between the crown 12 and the opening 18 at the base of the container. They can be slightly scalloped to increase the cross-sectional area of the venting path. But experience has not found that necessary. As shown in FIG. 3, The flats 36 that are shown are four in number and encompass about 50% of the circumference of the crown 12.

FIGS. 6 and 7 highlight the distinction between the portions of the crown 12 and groove 34 where the flats 36 have been cut and the portions of the grommet 30 where there are no flats.

FIGS. 6 and 7 show the relative dimensional arrangements in the grommet 30 when the grommet is in its relaxed state. This relaxed state is essentially the state in which the grommet is mounted in the charging opening 18 of the container prior to being forced into the sealing state shown in FIG. 5.

FIG. 8 through 11 show the technique by which the grommet of this invention permits ready loading of product into the container.

As shown in FIG. 8, product 42 is filled into the container 40 through the top opening 44. A piston 46 separates the product chamber from the propellant chamber 48.

As shown in FIG. 9, slight pressure through the opening 44 pushes the product 42 into conformance with the top of the piston 46 thereby eliminating air spaces between the piston 46 and the product 42. During this step, any such air that is being eliminated passes down the sides of the piston 46 and out of the passageway provided by the grommet 30 in its venting state.

As shown in FIG. 10, the next step is to admit air under relatively low pressure to push the piston 46 up in order to cause the product 42 to fill the top of the container 40. At this stage, the valve 50 is added. At this push up of piston 46 stage, air has to be vented into the lower chamber 48 (the propellant chamber) through the grommet 30 in its venting state.

After the product 42 has been appropriately positioned within the container 10, the grommet 30 is forced into its sealing state and then propellant is charged into the propellant chamber by the technique shown in greater detail in the '362 patent. This provides the state shown in FIG. 11.

The venting of air is useful to prevent air from going into solution in the product. Where the air does not go into solution, the venting assures that the FIG. 11 state is achieved in which optimum product and propellant charges are provided.

The use of this improved valve 30 for venting in connection with a piston 46 operated dispensing container is described herein. However, the venting is also useful when a pouch is used because the filling of the pouch causes the pouch to expand in volume thereby causing air to be vented out through the grommet 30 in its venting state.

The push down step shown in FIG. 9 is not always necessary. The push down step might not be necessary when loading low viscosity, highly flowable product. Such products can flow to conform to the upper surface of the piston. But that also requires venting since the high speed loading of product will trap air that must be vented. Accordingly, for some low viscosity products, the venting makes possible the simultaneous loading of product and the conforming of product to the shape of the piston. For more viscous product, the venting makes possible a separate step of pushing down on the product after the product has been loaded into the product chamber. But in both cases, the venting that this grommet 30 permits is necessary if the grommet is to be assembled with the can prior to loading product.

A presently preferred material for the grommet 10 is a thermoplastic polyester elastomer available from DuPont under the trademark Hytrel as mentioned in column 5 of the '362 prior art patent. It should be noted that the discussion of grommet material set forth in the '362 patent applies to the product of this application.

In one embodiment which is adapted to be used with the container having a 210 mil bottom opening 18, the following significant dimensions are involved. These values are approximate. A mil is one-thousandths of an inch.

OD Of Grommet Crown 12 217 mils OD Of Grommet Crown 12 at Flats 36 196 mils OD of Narrowest Part of Groove 34 207 mils OD of Ridge 32 243 mils OD of Neck 16 in Relaxed State 225 mils OD of Neck 16 in Sealed State 210 mils Height of Neck 16 in Relaxed State 15.5 mils Height of Neck 16 in Sealed State 42 mils Thickness of Sealing Ledge Provided by Ridge 32 9 mils

While the foregoing description and drawings represent the presently preferred embodiments of the invention, it should be understood that those skilled in the art will be able to make changes and modifications to those embodiments without departing from the teachings of the invention and the scope of the claims.

For example, the flats 36 need not extend to include a portion of the groove 34 if the diameter of the groove 34 is smaller than the flat distance across the crown 12. 

1. In a pressurized dispensing container, a grommet for sealing the opening through which a propellant charge is injected into the container, wherein the grommet has a crown, a base and a resilient stretchable neck between the crown and the base to permit the grommet to be in a sealed state when the neck is in a first extended position and to permit pressurized fluid to be charged into the base of a container through the grommet when the neck is in a second, more extended, position, the improvement comprising: an annular ridge above the neck an annular groove above said annular ridge and below the crown, the crown having a maximum diameter greater than the diameter of the charging opening of the container said annular groove dimensioned to fit within the charging opening of the container in a non-sealing state for the grommet, and at least one longitudinally extending venting channel along the crown so that when the grommet is in said non-sealing state air can enter and exit from the container through said venting channel during the filling stages of the container, said annular groove together with said venting channel positioned within the container in the sealed state of the grommet.
 2. The grommet improvement of claim 1 wherein: said venting channel is partially defined by a flat, said flat being on the surfaces of the crown and said groove.
 3. The grommet improvement of claim 1 wherein: there are four of said venting channels.
 4. The grommet improvement of claim 2 wherein: there are four of said flats creating four of said channels.
 5. The grommet improvement of claim 4 wherein: said four flats encompass approximately 50 percent of the circumference of the crown.
 6. The method of preparing a pressurized dispensing container containing a piston with product to be dispensed from a product chamber on the top of the piston and with propellant in a propellant chamber under the piston, comprising the steps of: holding a grommet in the charging opening at the base of the container in a first position that provides a venting of air in and out of the propellant chamber through a venting channel, said venting channel at least partially defined by the grommet, loading product to be dispensed into the product chamber, pushing product and piston into a fully downward position to minimize air between product and piston and thus venting gas through the venting channel, then applying gas under pressure through the venting channel to force the piston up and thereby minimize air at the top of the product in the product chamber, moving the grommet to a second position to provide a seal, and charging the propellant chamber with propellant through a charging channel in the grommet to provide pressurized product in the product chamber.
 7. The method of claim 6 wherein: said step of pushing occurs simultaneous with said step of loading.
 8. The method of claim 6 wherein: said step of pushing occurs after said step of loading.
 9. The method of preparing a pressurized dispensing container containing a piston with product to be dispensed from a product chamber on the top of the piston and with propellant in a propellant chamber under the piston, comprising the steps of: inserting a grommet into a charging opening in the base of the container to a first position that provides a venting of air in the propellant chamber through a venting channel, said venting channel at least partially defined by the grommet, loading product to be dispensed into the product chamber, then applying gas under pressure into the product chamber thereby pushing product and piston into a fully downward position to minimize air between product and piston and thus venting gas through the venting channel, then applying gas under pressure through the venting channel to push the piston up and thereby minimize air at the top of the product in the product chamber, moving the grommet to a second position to provide a seal, and charging the propellant chamber with propellant through a charging channel in the grommet to provide pressurized product in the product chamber.
 10. The method of preparing a pressurized dispensing container containing a barrier element with product to be dispensed from a product chamber on a first side of the barrier element and with propellant in a propellant chamber on a second side of the barrier, comprising the steps of: inserting a grommet into a charging opening in the base of the container to a first position that provides a venting of air in the propellant chamber through a venting channel, said venting channel at least partially defined by the grommet, loading product to be dispensed into the product chamber thereby expanding the product chamber, reducing the volume of the propellant chamber and venting air from the propellant chamber, through the venting channel of the grommet as the propellant chamber decreases in volume, moving the grommet to a second position to provide a seal, and charging the propellant chamber with propellant through a charging channel in the grommet to provide pressurized product in the product chamber. 